gulating or upper part. By lowering the under part, after having been raised, the valve in its bottom will be forced open by the pressure of the atmosphere, and the lower compartment will fill with air. On raising the bottom, the lower valve closes, and the air in the under part is compressed and forced through the valve in the partition, whence the weight of the top drives it through the tuyere, or nozzle. The pressure may be increased by putting weights upon the top. The bellows may be driven by machinery or power, where such can be procured, quite as well as by hand; but it is better, in such cases, to employ the fan-blast, as represented in Figs. 15 and 16. If the fan-blast can be obtained, it is preferable to the common bellows, as it is more uniform, and saves fuel; besides, its use improves the quality of the steel and iron.

The tuyere, or tue iron, is usually a simple block of cast-iron, as represented, of six or eight inches long and three inches square, with a tapered bore of one inch at the smaller, and three inches at the wider end. The narrow part, which is directed into the fire, can be made narrower by placing an iron ring, of more or less thickness, within the aperture. Tuyeres have been contrived of various forms; but probably none will be found superior to that above

described. Hot-air tuyeres have been used, but are
now generally abandoned. The water tuyere (Fig. 4)
is, on account of its durability, very valuable; but it
has the disadvantage of keeping the fire cold, which
is injurious to both iron and steel, but particularly
to the latter. Another tuyere, now coming very
much into use, is the "rotary blacksmith's tuyere."
This appears to be a very desirable addition to the
forge, as it affords the facility of increasing the size
of the aperture, and consequently the strength of
the blast, at any moment, even while at work. Of
this tuyere, (represented in Fig. 2,) E. Harris, of
Springfield, Mass., is the patentee.
are in a rotary, oblong ball, A, and
are of various sizes; so that a larger
or smaller one may be used by merely
turning the ball. The whole is con-
tained in a cast-iron box, closed on

The apertures

Fig. 2.

all sides. The great advantage of this tuyere consists in the fact that a small fire may be converted into a large one, or vice versa, by merely turning the hollow ball by means of an axle, which projects at one side of the box.

The form of the aperture of a tuyere is of considerable importance in the working of the fire. An almost cylindrical aperture, such as is represented

in Fig. 3, throws the blast in a compact, close, and

Fig. 3.

almost cylindrical current, into

the fire; and furnishes the kind of blast required for welding, soldering, and small work, where the heat is to be concentrated upon a particular point. By the use of this tuyere, a great saving in fuel is effected. To make a cylindrical blast, the cylindrical part of the aperture should be at least as long as the diameter of the same is wide.

Fig. 4.

A tuyere of the form shown in Fig. 4 throws the blast over a large portion of the fire; it is useful for heating, but unsuitable for welding iron. The nozzle from the bellows, or the blast-pipe, is in all cases fitted

closely into the tuyere, and surrounded by clay, or some other matter. A tuyere of the description shown in Fig. 3 makes a small, but intense heat; while one of the kind represented in Fig. 4 makes a larger fire, but lower heat.

FORGE FOR HARD COAL.

In working hard, or anthracite coal, no horizontal tuyere, nor any of the description above referred to, can be used to advantage. A small grate is laid in the bottom of the fire-hearth, space being left below it for the reception of ashes and clinkers; the blast is then introduced under the grate. Such an arrangement may be made at any common forge-fire; perfect forge is represented in Fig. 5.

but a more

This is a brick hearth, about thirty inches high and three feet square, in the centre of which is a square pit, into which the blast-pipe is conducted. At a distance or less, below

of six inches,

the top of the brick-work, a cast-iron plate is inserted,

Fig. 5.

in which is a square hole for the reception of the grate. A common stove-grate, four or five inches square, and fitting loosely into the cast-iron plate, is the kind generally used. A small opening, below

the grate, leads into the ash-pit, in order to carry off the ashes and cinders. On the right and left of the fire,

a wall of fire brick is erected, six inches in

height, which support an arch, also of fire-brick. This arch is movable, and consists of an iron frame, into which the fire-brick are firmly wedged. In the wall on the right hand is an opening, into which an iron trough, in the form of a hopper, is inserted, for the purpose of heating the coal before it is put on the fire. Fresh hard coal, when thrown suddenly on a hot fire, is liable to crumble into small pieces; the heating prevents this, and keeps the fire open, and free from fine coal. The top of the hearth, or brickpile, is covered by an iron plate. A fire of this kind is very advantageous for common smith-work; but a concentrated heat cannot be made in it.

The fire-hearth represented in Fig. 1 is commonly twelve or sixteen inches wide, and six inches deep. The tuyere dips a little into the fire. The hearth is built of brick or stone, thirty inches high, and is covered, in whole or in part, by an iron plate. At the left side, an iron trough for coal, and a similar one for water, are usually inserted. An iron coaltrough is advantageous in working bituminous, and also hard coal. The coal in the trough is soaked in water, which qualifies it for roasting or coking, and affords the additional advantage of more readily disengaging the sulphur of the coal. For charcoal, a water-trough only is necessary. Forge-fires for large